Counting direct-converting x-ray detectors or integrating indirect-converting x-ray detectors can be used in x-ray imaging, for example in computed tomography, angiography or radiography.
In direct-converting x-ray detectors, the x-ray radiation or the photons can be converted into electrical pulses via a suitable converter material. Examples of suitable converter material are CdTe, CZT, CdZnTeSe, CdTeSe, CdMnTe, InP, TlBr2, HgI2, GaAs, or other materials. The electrical pulses, for example voltage pulses, are interpreted by evaluation electronics, for example an integrated circuit (Application Specific Integrated Circuit (ASIC)), in an evaluation unit. In counting x-ray detectors, incident x-ray radiation is measured by counting the electrical pulses triggered due to the absorption of x-ray photons in the converter material. The height of the electrical pulse is generally proportional to the energy of the absorbed x-ray photon. This enables spectral information to be extracted by comparing the height of the electrical pulse with a threshold value. The evaluation unit can be connected to a carrier unit, for example a ceramic substructure, such that an increased mechanical stability can be achieved and a rewiring of the signal connections to downstream signal processing units can be provided. In order to counteract the incidence of scattered x-ray photons, an antiscatter grid can be embodied on the side of the converter element facing toward the radiation source.
DE 10 2012 213 410 B3 discloses a direct-converting x-ray radiation detector that has at least one electrode deposited on a semiconductor. The at least one electrode and the semiconductor are connected in an electrically conducting manner, the at least one electrode being embodied as transparent and electrically conductive.
A detector module for x-ray computed tomography apparatus is known from DE 101 38 913 A1, wherein a sensor array comprising a plurality of sensor elements is mounted on a front side of a printed circuit board. In order to increase the accuracy of the detector, it is provided according to the invention that at least one heating element is provided on the back side of the printed circuit board facing away from the sensor array for the purpose of heating the sensor array and a control electronics circuit arranged close to the heating element for the purpose of controlling the heating element.